"...who drinks the water I shall give him, says the Lord, will have a spring inside him welling up for eternal life. Let them bring me to your holy mountain in the place where you dwell. Across the desert and through the mountain to the Canyon of the Crescent Moon..."

Petra is one of the most powerful, but restricted Wonders in the game. Besides enhancing early trading, its main bonus can turn a desert into a veritable oasis, greatly helping the city. If one of your starting cities is close to a desert, you should absolutely try to build Petra; for this, you'll need to rush Currency. Even if few or no tiles can benefit, the extra trade route is more than worth the cost. One problem might be that the city next to the desert doesn't have good Production capabilities; if so, you will really have to juggle your Citizens to make the most of the limited resources available to you and, if possible, establish an internal trade route for extra resources.

This Wonder is perfect in areas with a large amount of desert hills, as the bonus applies on top of the 2 Production the hills provide, but otherwise it turns all regular desert tiles into the equivalent of plains tiles. Note that oasis tiles also get the bonus - only flood plains (non-hill tiles next to a river) don't get it. And naturally, any tiles with resources on them will benefit greatly as well!

Morocco and Arabia are the only civilizations that have a desert start bias, and are likely to get this wonder. A diplomacy-minded Arabia should get this wonder; a war-minded Arabia (with its Camel Archers) might prioritize mobilization instead. Morocco definitely should get Petra, as the effect stacks well with Kasbahs.

Constructed sometime around 1000 BC, the site of Petra in Jordan is among the most famous examples of rock-cut architecture in the world. Numerous intricately carved structures were cut into the sandstone walls of the desert canyons surrounding the area, as Petra came to serve as the capital city for the once-nomadic Nabataen people. The most famous of these structures, the Al Khazneh or "The Treasury," has been featured in numerous major motion pictures, notably a prominent role in "Indiana Jones and the Last Crusade" when the Al Khazneh was used to represent the location of the Holy Grail.